Electrical devices not having a built-in power supply generally have at least one electrical connecting line. An electrical connecting line of an electrical device may be either connected to the housing of the device via an electrical plug-in connection or led via a housing opening into the interior of the device, where internal device components are contacted. In the latter case, the cable is to be fastened to the housing so that the electrical connecting line is not damaged by small tensile forces acting on the cable. The means and arrangements used for this purpose are generally referred to as strain relief devices. The terms “electrical device” and “electric device” are to be understood herein broadly. In particular, these terms encompass connection sockets and plug-in connectors.
The functional principle of strain relief for a connecting line is based on fixing the connecting line in a clamping manner. The connecting line may be fixed in a clamping manner by joining together housing parts or by tightening a screw connection to the housing. In many cases, the housing of an electrical device is made up of two joinable housing parts. The housing parts join together and clamp the connecting line between them at a location provided for this purpose. However, this type of strain relief does not function as well when rigid connecting cables having relatively large cross sections are to be fastened to a housing. In particular, when multiple cables are to be attached to a housing, it is advantageous to provide fastening means particularly suited for this purpose.
DE 10 2010 007 093 A1 (corresponds to U.S. Publication No. 2012/0292098) describes an electrical device having a cable feedthrough through a housing wall. A connection socket for a photovoltaic system has two cable ports integrally formed on its housing. A relatively rigid, shielded high-voltage cable is led into the interior of the housing through a cable port. The cable is fastened by crimping a sleeve on the outer sheathing of the cable. An annular face on the sleeve is placed against the end face of the cable port. The sleeve is fastened by a union nut screw-able onto the cable port.
Establishing this type of cable fastening involves a relatively high level of assembly effort. This is firstly due to the crimping operation that must be carried out and secondly due to the comparatively large time expenditure for establishing the screw connection. Therefore, such a design has only limited suitability for electrical devices which are manufactured in large amounts and to which multiple cables are to be fastened.